Which device restrains fore and aft motion of a rotor blade at the drag hinge?

Which device restrains fore and aft motion of a rotor blade at the drag hinge?

• A. Blade Damper
• B. Blade Coning
• C. Autopilot
• D. Antitorque Pedal

Answer: (A)

Damping the blade’s fore-and-aft motion at the drag hinge is accomplished by the blade damper. The drag hinge allows a small amount of drag-induced movement as the blade flaps and sweeps through its cyclic motions, but without damping that motion can turn into vibrations and flutter. The blade damper absorbs energy as the blade tries to move along the drag axis, smoothing the motion and helping keep the rotor system stable. Blade coning is simply the upward bending of the rotor disk under centrifugal load, not a damping device. Autopilot and antitorque pedals perform other controls and don’t restrain blade motion at the drag hinge.

Damping the blade’s fore-and-aft motion at the drag hinge is accomplished by the blade damper. The drag hinge allows a small amount of drag-induced movement as the blade flaps and sweeps through its cyclic motions, but without damping that motion can turn into vibrations and flutter. The blade damper absorbs energy as the blade tries to move along the drag axis, smoothing the motion and helping keep the rotor system stable. Blade coning is simply the upward bending of the rotor disk under centrifugal load, not a damping device. Autopilot and antitorque pedals perform other controls and don’t restrain blade motion at the drag hinge.